In response to the challenging requirements of the ELT First Light Instruments RTCs, ESO triggered in 2018 an external prototyping contract with FORCE Technology as part of a wider package of RTC de-risking activities.

At the core of this development was the identification of CPU-based hardware configurations, along with software and communication paradigms enabling RTC deterministic performance while preserving reasonable long-term maintainability and obsolescence resilience.

The result hereof, the HRTCp (Hard Real Time Core prototype), is a full scale prototype consisting of standard off-the-shelf PC servers and networking.

Using Linux as a hardware adaptation layer, HRTCp implements ELT MCAO-size pseudo open-loop control (six LGS, 500 Hz frame rate), from decoding sensor image data to controlling the ELT M4 and M5 mirrors.

The talk presents the system architecture and points out some of the more interesting challenges and features of the resulting software system.

Results from operating the HRTCp in an environment with externally simulated sensor- and mirror systems are presented.

Niels Hald Pedersen, FORCE Technology

Poul-Henning Kamp, The FreeBSD Project